Trends in Atmospheric Carbon Dioxide

Summary

Charles David Keeling began measuring atmospheric carbon dioxide (CO2) in 1958 at the Mauna Loa observatory on the big island of Hawaii. This graph shows atmospheric carbon dioxide concentration in parts per million (ppm) by volume from 1958 to 2016. Worksheet also available in Spanish.

Spanish versions of these resources are also available for download (en Español).

Records from polar ice cores show that the natural range of atmospheric CO2 over the last 800,000 years was 170 to 300 parts per million (ppm) by volume. In the early 20th century, scientists began to suspect that CO2 in the atmosphere might be increasing beyond this range due to human activities, such as burning fossil fuels and changes in land use, but there were no clear measurements of this trend. Charles David Keeling began measuring atmospheric carbon dioxide (CO2) in 1958 at the Mauna Loa observatory on the big island of Hawaii. This graph shows atmospheric carbon dioxide concentration in parts per million (ppm) by volume from 1958 to 2016.

Download the educator guide PDF, which includes questions to guide a class discussion on the graph characteristics and what the data show.